General Synax of html5 is
<!DOCTYPE html> specifies that this document is html 5 document and you can use all html5 tags here.
<head> specifies that this portion contains heading information of page we can use many other tags here like <title> which is used to specify the title of page and may other.
<body> we put the contents which you would like to display on browser.
Inside body tag we use many different html tags to proper formatting the data.